Hydraulic excavators are a type of work vehicle that is provided with a counterweight. The counterweight is provided to a rear portion of a main body frame in order to balance the vehicle body. A concave portion is formed on a front surface of the counterweight in order to provide an internal space for disposing an engine, a radiator, and similar devices (see Japanese Patent Publication No. 2004-11176). The concave portion is shaped so as to indent rearward from a front surface side, and covers the rear of the internal space. The top and front of the internal space are each covered by a cover member. The cover members are attached to and supported by a plurality of column members and beam members provided upright on the main body frame (Japanese Patent Publication No. 2006-335329).